2nd Summit Day 2

09-Nov-2011, Mozilla SF. Video (1.1GB flash .flv, 4 hours)

Attendees

Zack Weinberg
Zooko
David-Sarah
Brian
Shawn
Mark Seaborn

Ideas

Shawn: would be nice to have a more traditional username/password web frontend
- I (warner)'m imagining an IService, listening for HTTP on a different port than the main WEBAPI port, with a public URL. You submit username+password, get a cookie, present a filename. The gateway translates that into a filecap.
- maybe store one rootcap per username. use bcrypt/scrypt to defer exposure until user submits password.
- adding ACLs: either put a table in the frontend (username->file list), or put ACL data in dirnode edge metadata and have frontend compare it against a username
- sharing to public: tell frontend a filename/dirname and ask to make it public, it returns a tinyurl. Just like a tinyurl except it's a proxy instead of a redirect.
- sharing to an individual: maybe have an encryption pubkey for each account, Alice tells frontend "share my ~/foo with user=Bob", frontend encrypts a note to itself with Kbob, later when Bob logs in, his password bcrypt-unlocks the decryption key Kbobpriv, decrypts the note, gets the dircap, adds to a table for Bob, lets him enumerate a list of inbound shared directories
zwol describing a Tor project, making Tor traffic look like other traffic: WoW, other web browsing. "Stegatorus"?
zwol thinking about censorship-resistance, content-centric networking

Control Panel

- Brian explained requirements for a tahoe web-control-panel:
  - examine/control Agent things like periodic backup jobs (local dir,
    dircap, schedule, status, progress), lease-renewal/repair jobs
    (dircap, schedule, status, progress)
  - not using browser ambient authority, accessed through NODEDIR (iff
    you can read/write to NODEDIR/private, you should be able to get to
    the Web Control Panel), 
  - not scoped to a particular filecap/dircap
  - yes scoped to "client authority" (i.e. an "Account", q.v. Accounting,
    for general uploads and maybe repair), or local-disk-authority
    (backup jobs), or server admin (for the server side of Accounting)
  - ok to have no-JS and yes-JS options, ok if the no-JS option is less
    pleasant
- David-Sarah, Zack, Shawn designed a scheme
  - writes a "control.html" into NODEDIR/private/
  - "tahoe control" launches browser with `file://.../control.html`
  - yes-JS version:
    - it contains one big `<iframe src="<http://WUI/control#SECRET>">`
    - that page contains JS which pulls the secret out of the fragment,
      then does lots of XHR with the secret to present the control panel
  - no-JS version:
    - it contains a form with a big "Start" button and a secret in a
      hidden form-post argument
    - that returns a page with lots of forms, secrets in hidden
      post-args. All links are POSTs. "back" won't be pleasant (requires
      a 're-submit form?' confirmation each time).
  - benefits: keep secret out of address bar, out of Referrer header
- other useful techniques:
  - to limit the lifetime of a powerful secret, 'tahoe control' can write
    a new secret into NODEDIR just before launching the browser, and the
    node can erase or change the secret just after accepting the
    resulting browser hit.
  - splitting the webapi into multiple origins is becoming more
    important: probably starting with one port for (control-panel,
    welcome, node-status, WUI-dirnodes, download-only WAPI), and a second
    one for (WUI-documents) that could be executable.
- [whiteboard](../raw/attachments/Summit2Day2/day2-webcontrol.jpg)

Accounting Review

- Brian presented his Accounting branch
  (<https://github.com/warner/tahoe-lafs/tree/accounting>) , only looking
  at the delta between the '466-ed25519' branch and the 'accounting'
  branch (it builds upon the #466 work)
- deferred discussion of leasedb crawler and race conditions, that
  requires more serious design work. David-Sarah and Brian will huddle on
  it, probably online later
- approach seemed good, code is still incomplete
- needs: more tests, usable control panel, refinement of "account
  message" concept
- need to carefully plan the merge with LAE's s3-backend: they overlap a
  lot. Removing leases from shares helps a bunch. s3-backend introduces
  async share-crawlers, accounting removes one big crawler but adds a new
  small one, which might need to be async-ified if that still seems like
  a good idea.
- consensus was that #466 should definitely land first. But then whether
  accounting should land before s3-backend, or other way around, was
  unclear. accounting needs more development work before it's ready for
  landing, s3-backend might be closer. But some co-evolution and
  anticipatory refactoring should make things easier for everybody.
- brief discussion about branches in Git vs Darcs, specifically for
  working on projects like this. Brian anticipates pain and suffering
  trying to test merges of s3-backend (managed in a darcs branch) with
  his accounting work (managed in git branches). David-Sarah suggested
  applying the git/darcs bridge on a branch too, brian skeptical.